American Nurseryman, April 2014

flumioxazin SureGuard 51WDG Rate 025 to 038 lb ai A 8 to 12 oz A SureGuard Time Apply before or after weeds emerge Kills existing annual weeds if weeds are less than 2 inches Remarks Can be used safely on established and dormant conifers Also can be applied to established deciduous crops check label with directed sprays as long as contact with foliage and green bark is avoided Injury to linden Tilia spp which has a thin green bark when young has been noted in several Oregon nurseries Payload is similar to SureGuard and is labeled for use to maintain bare ground and non crop areas Site of action Group 14 protoporphyrinogen oxidase inhibitor Chemical family N phenylphthalimide flumioxazin BroadStar 025G Rate 0375 lb ai A 150 lb A BroadStar Time Apply to weed free containers Caution Foliage of desirable crops must be dry at the time of application Wet foliage will trap granules on leaf surface and burn foliage Site of action Group 14 protoporphyrinogen oxidase inhibitor Chemical family N phenylphthalimide isoxaben Gallery 75 DF Rate 0495 to 099 lb ai A 066 to 133 lb A Time Apply in late summer to early fall in early spring or immediately after cultivation Apply to debris free soil surface Remarks Identify weeds and adjust rates according to charts on label Activate with 05 inch water or shallow cultivation before weeds emerge Chemical is stable enough when left on soil surface for 21 days Caution Do not apply to newly transplanted crops until media settle Site of action Group 21 inhibits cell wall synthesis Site B Chemical family Benzamide isoxaben trifluralin Snapshot 25TG Rate 25 to 5 lb ai A 100 to 200 lb Snapshot A Time Apply to soil that is free from weeds and debris Remarks Soil must be settled with water and free from cracks after transplanting Activate within 3 days using 05 inch of water or shallow cultivation before weeds begin to emerge Follow label instructions for repeat treatments Caution Do not apply to unrooted liners or cuttings bedding plants or new planted ground cover Site of action isoxaben Group 21 inhibits cell wall synthesis Site B trifluralin Group 3 microtubule assembly inhibitor Chemical family isoxaben benzamide trifluralin dinitroaniline napropamide Devrinol 2G or Devrinol 50DF Rate 4 lb ai A 8 lb A Devrinol 50DF Time Consult label for crops listed Apply November to February and irrigate if no rain falls within 2 to 3 days or apply March through October and irrigate within 24 hours to wet soil 2 to 4 inches deep Remarks Shallow mechanical incorporation improves performance Use higher rates if weed infestations are severe or broadleaf weeds predominate Inhibits root growth Site of action Group 15 inhibits very long chain fatty acid synthesis Chemical family Acetamide norflurazon Solicam Established stock only Rate 3 lb ai A Time Apply in fall or spring to bare soil after nursery crops are established Remarks Rain must be adequate before weeds begin to emerge Read label thoroughly about site soil crop rotation and mixing precautions Inhibits yellow pigment formation bleaching green chlorophyll Caution Do not apply to cherry grape or caneberry nurseries Site of action Group 12 bleaching inhibits carotenoid biosynthesis Chemical family Pyridazinone oryzalin Surflan AS Rate 2 to 4 lb ai A 2 to 4 quarts A Surflan AS Time Apply any time to bare soil Activate within 21 days with 05 inch water Wait at least 90 days before repeating application Apply only to established plantings Remarks Inhibits cell division or mitosis primarily in roots Site of action Group 3 microtubule assembly inhibitor Chemical family Dinitroaniline oxadiazon Ronstar G or Ronstar 50WSP Rate 2 to 4 lb ai A 100 to 200 lb A Ronstar G Time Apply uniformly with granular applicator any time to weed free soil and when plants are dry Remarks Irrigate with 025 to 033 inch water immediately after applying do not incorporate mechanically Weeds in the pink family chickweed mouseear chickweed pearlwort are resistant Controls weed seedlings by contact action during emergence Site of action Group 14 protoporphyrinogen oxidase inhibitor Chemical family Oxadiazole pendimethalin Pendulum 2G Pendulum WDG or Corral 268G Rate 15 to 2 lb ai A 75 to 100 lb A Pendulum 2G Time Apply at planting or before weed seed germinates Soil should be loose and free from established weeds Remarks Water within a few days to activate herbicide before weeds emerge Inhibits mitosis in roots and shoots Site of action Group 3 microtubule assembly inhibitor Chemical family Dinitroaniline prodiamine Barricade 4L or RegalKade Rate 065 to 15 lb ai A 21 to 48 fl oz A Barricade Time Apply to weed free site Remarks Follow with 05 inch rain or irrigation or shallow incorporation Caution Do not exceed maximum rate on label in a 12 month period Do not apply to recently planted red maple Acer rubrum liners this species is not labeled and severe girdling has been observed in several Oregon nurseries Site of action Group 3 microtubule assembly inhibitor Chemical family Dinitroaniline pronamide Kerb Established stock only Rate 1 to 2 lb ai A Time Apply in fall before leaves drop or soil freezes Or apply from early to midwinter west of the Cascades to soil relatively free of plant residues Remarks Requires soil moisture from rain or irrigation to activate do not incorporate mechanically Use lower rates for annual grasses and light texture soils higher rates for perennial grasses and heavier soils Control of established grasses is slow Degraded by microorganisms in warmer weather Use on nursery stock established at least 1 year and seedlings that are at least 1 year old Inhibits root growth Caution A restricted use pesticide Site of action Group 3 microtubule assembly inhibitor Chemical family Benzamide S metolachlor Pennant Magnum Rate 124 to 248 lb ai A 13 to 26 pints A Pennant Magnum Time Apply any time to weed free soil as a spray directed to base of ornamentals transplanted at least 10 days Remarks Activate herbicide with light irrigation Use lower rates on sandy soils and reduced weed infestations Gives about 60 days control less under very wet conditions Suppresses yellow nutsedge when applied preemergence and activated with adequate water Caution Do not use on seedbeds or unrooted cuttings Inhibits seedling roots and or shoots Site of action Group 15 inhibits very long chain fatty acid synthesis Chemical family Chloroacetamide simazine Simazine 4L and others Established stock only Rate 2 to 3 lb ai A Time Apply at least 1 year after transplanting to weed free soil and activate with rain or sprinkler irrigation Site of action Group 5 photosystem II inhibitor Chemical family Triazine trifluralin 4HF or 10G products Rate 4 lb ai A Time Apply to established nursery crops before weeds germinate Incorporate with 05 inch of irrigation or rain within 3 days of application Inhibits Controlling Weeds Continued from page 13 Continued on page 16 14 April 2014 American Nurseryman www amerinursery com

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